Yang Yuchong, Hu Hao, Guo Yuanyuan, Xia Andong, Xu Jiang-Fei, Zhang Xi
Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing, 100084, China.
The Key Laboratory of Photochemistry, Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Macromol Rapid Commun. 2020 Dec;41(24):e2000080. doi: 10.1002/marc.202000080. Epub 2020 May 17.
The supramolecular polymeric radicals are developed to promote the generation efficiency and stability of naphthalenediimide (NDI) radical anions. To this end, a water-soluble bifunctional monomer bearing two naphthalene-viologen end groups and a NDI center is designed and synthesized. The supramolecular polymeric NDI radical anions are fabricated on the basis of host-guest complexation between the NDI-containing bifunctional monomer and cucurbit[8]uril (CB[8]) and followed by the photoinduced electron transfer process under UV light irradiation. The electrostatic effect of CB[8] and the bulky and rigid structure of supramolecular polymer are combined to stabilize the excited state of NDIs and NDI radical anions, contributing to the high enhancement of the formation of NDI radical anions with excellent stability. It is found that the highest occupied molecular orbital energy and lowest unoccupied molecular orbital energy of NDI are also lowered by the formation of supramolecular polymer. In addition, the supramolecular polymeric NDI radical anions could be utilized as a supramolecular photoreducing agent to reduce cytochrome C with a higher efficiency. It is anticipated that other radicals can also be stabilized through this strategy, and this line of research may lead to the development of novel polymeric radical materials.
超分子聚合物自由基的开发旨在提高萘二酰亚胺（NDI）自由基阴离子的生成效率和稳定性。为此，设计并合成了一种带有两个萘 - 紫精端基和一个NDI中心的水溶性双功能单体。基于含NDI的双功能单体与葫芦[8]脲（CB[8]）之间的主客体络合作用，随后在紫外光照射下进行光诱导电子转移过程，制备出超分子聚合物NDI自由基阴离子。CB[8]的静电效应与超分子聚合物庞大且刚性的结构相结合，稳定了NDI和NDI自由基阴离子的激发态，有助于高效增强形成具有优异稳定性的NDI自由基阴离子。研究发现，超分子聚合物的形成还降低了NDI的最高占据分子轨道能量和最低未占据分子轨道能量。此外，超分子聚合物NDI自由基阴离子可用作超分子光还原剂，更高效地还原细胞色素C。预计通过该策略还可稳定其他自由基，这一系列研究可能会推动新型聚合物自由基材料的发展。
